Import projects is a eclipse dialog. you can select the radio button and do the setText into the textbox.
bot.tree().expandNode("General").select("Existing Projects into Workspace");
bot.button("Next >").click();
bot.radio("Select root directory:").click();
bot.text(0).setText("directory path"); //you have to specify your project folder path here

If you want to handle native OS dialogs. you have to use presShortcut and keystrokes for that.